There is no reason to doubt that Adam and Eve as described in scripture are historical people. Again, the traditional view of Adam and Eve is not what I propose but that aside, scripture treats these two people as having a historical context.
The narrative was written to the ANE culture which means that the ANE area and populace was the only group affected by God’s dealings. Even in the traditional context, not all people were wiped out since those on the ark were saved as well as the animals that were put into the ark. You are still trapped in the traditional meaning of the text and I realize the difficulty in thinking and reasoning as those who inhabited the ANE but that is the only way that we can find the intended meaning of these ancient texts.
I think it is safe to assume that localized floods occurred in the ANE during the time when the biblical flood occurred. It is without reason to deny that such events occurred, so I don’t need proof that a massive catastrophic flood occurred in a localized area. To assume that catastrophic events never took place in the time of the ancients, is ludicrous. I believe the flood account because it is true: see below.
No one ripped off anything. As I pointed out before, a common narrative among so many ANE cultures demands a common event. There is no reason to “rip off” another culture’s worldview unless that worldview aided said culture in understanding the cataclysmic events that mankind had no control over and could not explain. This common thread among so many cultures concerning a horrific flood is another reason why I believe the event to be historical.
It is often said that many of these OT biblical accounts are based on mythology. If one accepts the validity of comparative studies, then one will recognize that the mythologies of the ancient cultures were in fact their science (Walton 14). The purpose of science is to aid in understanding the environment that one inhabits and to determine why events take place as they do and to try and control these events. That is what the ancients did in what we call mythology but to them it was science. So, if I say the science of the ANE, then I am referring to their mythology. The ancients attempted to control environmental events by appealing to the gods. To them, every event, what we would call natural events, was at the behest and control of the gods. There was no such thing as “natural.” All happenings that were out of the control of mankind were in the control of the gods.
I am not sure that I know what you are saying here but God accomplished what He desired. The flood took place in the same area from which the accounts of the flood originated. Remember, there was no knowledge of any other area than what the ancients had experienced. So to them, the only "earth" or "world" that existed was what they had experienced.
Works Cited
Walton, John H. The Lost World of Genesis One: Ancient Cosmology and the Origins Debate. Downers
Grove: IVP Academic, 2010. Kindle file.